Steam plant



Oct. 2, 1934. D, W RUDORFF 1,975,519

STEAM PLANT BY /TZQM ATTORN EY OC- 2, 1934. D, w. RUDORFF STEAM PLANTFiled sept. 25, 1951 V2 sheets-sheenu www dNNV

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ATTORNEY Patented Oct. 2, 19.34

UNITED STATES PATENT OFFICE y toy The Superheater Company,

New York,

Application September 25, 1931, Serial No. 565,009 g 4 Claims.

The present invention relates to steam generators and aims to provide anarrangement having high eiiiciency and flexibility of operation.

In operating steam generating plants it is often desired to regulateclosely the temperature of some stream of fluid, such as steam or water,in the plant. Owing to the variations in steam output and in the heatgenerated in the furnace from time to time, difficulty has beenexperienced in maintaining the desired regulation of the temperature ofthe selected fluid or uids.

It is an object of myinvention to provide an arrangement whereby thisdiiliculty may be overcome.

In accordance with my invention, a portion of the heat generated in theboiler furnace is abed out in the appended claims.

sorbed in steam generating tubes in the usual manner, but anotherproportion of such heatis absorbed by a circulating fluid, preferablyone` way of example from a number of possible embodiments thereof andsuch a description will now be given in connection with the accompanyingdrawings in which Fig. l is a sectional elevation, somewhat diagrammaticin character, of a steam generating system in accordance with myinvention.

Fig. 2 is a sectional elevation, somewhat diagrammatic in character, ofan arrangement in accordance with my invention, but including featuresin addition to those shown in Fig. 1.

'I'he steam generating system illustrated in Fig. 1 includes a boiler l0having a furnace 12, generating tubes 14 and 16 and a superheater 18,all of conventional type. 20 is a vertical ue connected to receivecombustion gases from the boiler 10 and assumed to have a downward flowof gases therein. In flue 20, I have shown a plurality of groups 22 and22a of heat absorbing tubes connected for ow of fluid through the twogroups in series and forming a portion of a circulating system 24 forabsorbing heat from the gases flowing through ue 20 and transferring itto vfluids having a utility in connection with the boiler 10,.Preferably the fluid in such circuit or system is one having a highboiling point such as diphen'yl, mercury, or diphenyl-oxide. However, Ido not limit Amyself to this. In the arrangement of Fig. 1, thecirculating fluid is forced around a circuit by a pump 26.l Connected'tothe outlet of pump 26 by a pipe 28 is a .heat delivering coil 30 formingpart of a water preheating apparatus 32 connected to receive water froma source not shown by means of pipe 34 and connected to pipe 36 todeliver to the feed pump 38 for the boiler 10. The coil 30 has avalvedby-pass 40 therearound so that, when desired, some of the heattransferring liquid in system 24 can be shunted around coil 30 and theliquid delivered to the pipe 42 on the outlet side of such coil. at ahigher temperature than would otherwise be the' case. The reason forsuch by-pass will appear presently. 'I'he pipe 42 is arranged to deliverthrough a storage tank 43 for the circulating liquid into the lower oneof the heat absorbing coils 22. From the lower coil 22 the circulatingliquid passes to the, upper-coil 22a through a junction box 44 at whichpoint a branch delivery pipe 46 is taken olf to a heat absorbingapparatus. At the upper or delivery end of the upper coil 22a a seconddeliveryl pipe 48 is taken oil. Pipe 48 connects with a heat deliveringcoil 50 shown as the heating element of an economizer 52 which receiveswater from said boiler feed pump 38. The pipe 46 connects with a heatdelivering coil 54 which is shown as the heating element of an airheater 56 for heating air for the furnace 12. 'Ihe outlet pipes 58 and60 of the coils 50 and 54 respectively connect at point 62 and areconnected to the circulating pump 26 by a pipe 64. Valves are providedat 66 and 68 in pipes 46 and 58 lrespectively so that the relativeamount of heating uid flowing through coils 50 and 54 respectively maybe varied to the extent necessary to regulate the temperatures of thefluid delivered by heater 52 as desired. In the arrangement shown, theheater 52 being an economizer, its advantageous use is to maintain thetemperature of the water delivered therefrom to the boiler as nearly aspossible at the given temperature equal to the boiling point of thewater in boiler 10. The economizer 52 therefore will preferably beoperated as a constant temperature apparatus and the air heater 56 `as avariable temperature device. However, the temperature of the uiddelivered by the heating coils 22 and 22a not necessarily being inproportion to the quantity of water passing through economizer 52, it isdesirable to have means for regulating the amount of heat delivered toooI economizer 52 other than the valves 66 and 68. The by-pass 40 inconnection with the water heater 32 previously mentioned affords suchmeans. By opening the valve in by-pass 40 more or less, the circulatingfluid in system 24 is delivered tothe coil 22 at somewhat highertemperature than' would otherwise be the case and the temperatureavailable for use in the heating coil 50 is therefore increased.

In the arrangement shown in Fig. 2, I have incorporated three heatingcoils 22, 22a, and 22h. The boiler 10a. shown in Fig. 2 is of somewhatdifferent type from that shown in Fig. 1, but this fact does not affectthe operation of the system as such. In the system 24a illustrated inFig. 2, however, as distinguishing from the system of Fig. l, I utilizethe liquid circulating in the heat transferring system 24a to supply aportion of the heat required for heating the steam delivered by thesuperheater 18a. The feature of heating the outgoing steam partly by thecirculating fluid makes it preferable that an additional heat absorbingcoil 22h be included in system 24a. However, I do not limit myself tothis. The heat transferring system 24a shown in Fig. 2 includes a pump26 delivering through suitable connections to the lower heat absorbingcoil 22, the three such coils being connected in pairs at junctionpoints 44 and 44a. 'I'he two lower coils 22 and 22a supply an economizer52 and an air heater 56 in substantially the same manner as previouslydescribed in connection with the economizer and air heaterdn Fig. l. Theupper heat absorbing coil 22D, however, delivers to a discharge pipewhich connects to a heat delivering coil 72 in heat exchanger 74 forpartially superheating the steam from boiler 10a. The steam to be heatedin device 74 is taken from the steam drum 76 of boiler 10a through pipe78 to the heat exchanger '74 and delivered from exchanger 74 throughpipe 80 to the superheater 18a which is arranged to receive heatdirectly from the gases from the furnace 12a of boiler 10a. Preferably,a steam reheater 82 is included in the system illustrated in Fig. 2. Asshown, heating fluid for the reheater 82 is taken from the pipe '70 bypipe 84 which branches from pipe 70 at point 86 and connects to the heatdelivering coil 88 in the reheater 82. In Fig. 2, the heat deliveringcoils of devices 52, 56, '74 and 82 are co-nnected by suitable outletpipes into the common main 90 which connects with the heat deliveringcoil 30a in the water heater 32a. From coil 30a, circulating liquid insystem 24a is delivered to the storage tank 43a from which it may returnto the pump 26 through the pipe 92. It will be seen that the pipingconnections in Fig. 2 are slightly different from those in Fig. l butthe operation of the system is not altered by this fact. It will be seenalso that no by-pass is shown in Fig. 2 around the heating coil of thewater. heater 32a since it is considered that the system shown in Fig. 2has sufcient flexibility so that such by-passing is not necessary. Itwill be understood, however, that in Fig. 2 it is desired to maintainthe temperature of the steam vat the outlet of the superheater 18a.substantially constant and that the valves in the lines 84, 48 and 46are manipulated in use so that the steam delivered from heat exchanger74 will have the proper temperatures to compensate for the varying ratesof heat absorption in the superheater 18a. In respects not mentioned,the system 24a of Fig. 2 is the same as the system 24 of Fig. 1.

A feature of the systems shown in both Figs. l and 2 is that waterheaters 32 and 32a have considerable storage capacity so that heatcontained in the circulating liquid in systems 24 and 24a, but notabsorbed in devices 52, 56, 74 and 82, or by the amount of feed waterflowing to devices 32 or 32a to satisfy the requirements of the boilersat the time, may be absorbed by additional feed water admitted toheaters 32 or 32a by speeding the feed pumps 38 somewhat more thannecessary to supply the water going to the boilers at the time. Theflnal temperature of the circulating fluid returned to coils 22 isthereby kept low and the overall efliciency kept high.

When the heat transferring liquid circulated in systems 24 and/or 24ahas a relatively high boiling point compared to water, the pressure insuch system is relatively low compared to the .boiler pressure providedthe circulating liquid is permitted to vaporize in the sections 22 andthe like and is condensed in the heat delivering coils 52, 56, 74 and82. I do not limit myself to this, however, as it is often desirable toprevent vaporization in systems such as 24 and 24a to thereby increasethe temperature of the circulating liquid and the maximum possibletemperature delivered thereby. When vaporization of the circulatingliquid is prevented, it is especially desirable to use a high boilingpoint circulating liquid to keep down the pressure within the systemsuch as 24 or 24a and thereby to keep down the material and cost of thesystem.

It will be seen that the system in accordance with my invention operatesat a high over-all heat eiciency since the heat transferring liquid inthe systems 24 and 24a or the like pass through the heating coils 22,22a and 22h in the opposite direction from the flow of furnace gases inthe iiues 20 in which the heat absorbing coils are placed, and that theheat transferring liquid can be introduced into the heat absorbing coilfarthest from the boiler furnace at a comparatively low temperature,thus minimizing the heat carried away in the stack gases. In each ofFigs. l. and 2, l' have illustrated the heat delivering coils 50 and 54and the like as connected in parallel. However, I do not limit myself tothis, since somewhat analogous results may be obtained by connecting theheat delivering coils in the superheater 74, the economizer 52 and airheater 56 in series and providing Valved bypasses around such coils. Itwill be seen also that a system in accordance with my invention is veryflexible and can be operated very conveniently to maintain thetemperature of fluid delivered by a given device very close to thatpredetermined for it.

What I claim is:

1. The combination of a boiler, a furnace therefor, a circuit containinga heat transferring fluid and having a portion arranged to absorb heatdeveloped in said furnace, said heat absorbing portion being so arrangedwith respect to combustion gases in said furnace as to produce in saidheat absorbing portion zones containing fluid of different temperature,and a plurality of heat delivering portions, connections whereby each ofsaid heat delivering portions receives fluid of different temperaturesfrom said heat absorbing portion, and means whereby different fluidshaving normallydierent initial temperatures absorb heat from differentones of said heat delivering portions, said connections so arranged thatthe cooler heating fluid flows to the lill@ heat delivering portionacting to heat the cooler one of said heat absorbing uids.

2. The combination of a boiler, a furnace therefor, said boiler having abank of generating tubes receiving gases from said furnace. a iluearranged to receive said furnace gases which have passed said bank, acircuit containing a heat transferring uid and having a portion arrangedin said flue to absorb heat from gases therein and having a plurality ofheat delivering portions, Ian economizervhaving a heating coil arrangedin said circuit to be heated bysaid iuid, an air heateralso having aheating coil arranged in said circuit to be heated by -said uid, and asteam superheating means having a heating coil arranged in said circuitto receive said uid.

3. The combination of a boiler, a furnace therefor, a circuit containinga heat transferring fluid and having a portion arranged to absorb heatfrom the gases from said furnace at a point following the boiler and aplurality of heat delivering portions, said heat absorbing .portionbeing arranged for iiow of duid therein in a direction counter to thei'iow of the gases, means whereby different fluids having normallydifferent initial temperatures absorb heat from dinerent ones of saidheat delivering portions, a connection leading to one of said heatdelivering portions from the hotter end of said absorbing portion and aconnection leading to another of said heat delivering portions from apoint of intermediate temperature of said heat absorbing portion,

'and a means whereby the output of one of said bustion. Y

DAGOBERT W. RUDORFF.

